4.1.3. Inversion Program

The inversion is carried out using the h3dtdinv_v2.exe executable program and an input file that MUST be name h3dtdinv.inp. To run the executable, open a command window and type the following:

../../_images/run_h3dtdinv.png

4.1.3.1. Units

  • Electric field data: Ex, Ey and Ez in units V/m

  • Magnetic field data: Hx, Hy and Hz in units A/m.

  • Magnetic field data: dBx/dt, dBy/dt and -dBz/dt in units T/s. The vertical component of dB/dt is represented using -dBz/dt due to a long-standing plotting convention

  • SAM data: The projection of the anomalous H-field along the direction of the Earth’s magnetic field in units A/m

  • Conductivity model: S/m

  • Reference/starting conductivity model: S/m

  • Model/interface weights: unitless

Important

Any combination of data, electric and or magnetic field components, can be be inverted. A specified flag at the start of the observations file can be used to omit columns or individual datums. However, SAM data is modeled on its own.

4.1.3.2. Output Files

The program h3dtdinv_v2.exe creates the following output files:

  • dpred_0.txt data predicted using the starting model or forward model

  • inv_xx.con: recovered model at iteration ‘xx’

  • dpred_xx.txt data predicted using model ‘xx’

  • inv.con: final conductivity model

  • h3dtd_v2.log: log file for the inversion

  • h3dtd_v2.out: stores details regarding the inversion